Field of the Invention
The present specification relates to suspensions provided in a snowmobile.
Description of the Related Art
Snowmobiles include skis disposed on the right and left sides of the vehicle frame and supported by arms connected to the vehicle frame so that the skis are can move up and down. Suspensions are connected to the vehicle frame and the arms. Each of the right and left suspensions includes a spring structure and a damper, and is expandable and contractible according to the vertical movement of the arm. When the vehicle body is going to incline toward the lateral side during turning or just before turning, the damper moderates the movement of the vehicle body and thus contributes to a comfortable ride. In most of conventional snowmobiles, the left and right suspensions are structurally independent of each other.
Japanese Patent Laid-Open No. 61-238564 (hereinafter referred to as Patent Document 1) and US Patent Application Publication No. 2012/0112424 (hereinafter referred to as Patent Document 2) disclose snowmobiles including air springs respectively provided in left and right suspensions. Unlike in the conventional snowmobiles described above, in the snowmobiles disclosed in Patent Documents 1 and 2, the left and right air springs are directly or indirectly connected to each other.
In the snowmobile of Patent Document 1, the air chamber 17 of the air spring forming the left suspension and the air chamber 17 of the air spring forming the right suspension are each connected to an air reservoir 20 via an air passage 21. When the vehicle turns, a valve 22 in the air passage 21 connected to the outer air spring is closed, which allows the outer air spring to exert sufficient spring force.
In the snowmobile of Patent Document 2, the air chambers formed in the left and right air springs 58O and 58I are connected to each other via pipes 70O and 70I. When the snowmobile slides laterally on a slope as shown in FIG. 2 of Patent Document 2, air flows from the air chamber of one air spring to the air chamber of the other air spring via the pipes 70O and 70I. This allows the driver to easily tilt the vehicle body when the snowmobile slides on a slope.